Steve,
As for the restaurant, I agree with the others - Pretty average, but it gets the job done.
For the FBO... Well, Airnav only has one now (though that certainly doesn't mean there's only one) but if Janesville Jet Center really is the only one left, they earned it. Fuel prices aren't stellar but they're reasonable, service is excellent, people are friendly. Diverted there once due to T-storms on the way home and the owners gave us a ride to a fast-food joint and then to the bus station to finish the trip to Madison. They certainly don't live down to the "Jet Center" name.
Other options - Well, I don't think there's a better option than JVL within a strict 30nm of JVL, but there's a couple of others *just* outside that range. Actually, it sounds like you're coming in fairly late so that leaves out MSN as the Jet Room will be closed, though MSN does have several courtesy cars available. But, my first choice for an alternative to JVL for you would be RYV - Wisconsin Aviation is also the FBO there, and they're great. There are several options for food right nearby, all within about a 5-minute walk: Steakfire is my favorite, it's a grill-your-own-steak type of place (or they'll grill it for you too), food is excellent, prices are reasonable. There's also a Perkins, which is certainly nothing special but there are discount coupons available for them at the FBO. Finally, if you want to get in and out quick, there's a Culver's as well - It's fast-ish food (made to order, but as quick as that gets) but it's the best burger I've had at outside of sit-down restaurants.
Sheboygan is an excellent stop for the way out - The restaurant is truly excellent, easily one of the top three airport restaurants I've ever been to. It's a bit difficult to find - It's not well marked. It's in the big gray building southeast of the approach end of runway 3, but there's no signs on the air side indicating that.
I'd also offer to meet you at MSN or C29 or wherever, but I'll be in Washington until Sunday night... So I'll see you at OSH!